I would not use any less than 15 throwing a spinnerbait. That's what I use most of the time throwing traps unless the grass is really thick and I need to keep it a little higher in the water column and I'll go to 20 then. The only time I throw 12 is when I'm cranking deep diving crankbaits and I need to get them down as deep as possible. I've had really good luck out of the seaguar red label.